The present invention relates to a sorting apparatus for sorting bodies suspended in a liquid according to the sizes of the bodies and, more particularly, to a sorting apparatus for sorting cleaning elastic balls used for cleaning tubes of heat exchangers in accordance with relative sizes of the cleaning balls.
Plants having steam turbines incorporate a condenser which is usually a heat exchanger of shell-and-tube type. For maintaining the desired high efficiency of the plant, it is necessary to clean inner surfaces of the cooling tubes of the condenser by removing mud and other contaminants attached to the tube inner surfaces. Previously, in order to keep the tube inner surfaces clean, elastic cleaning balls such as, for example, sponge balls have been fed into the cooling water to circulate through the condenser together with the cooling water thereby mechanically removing the contaminants from the inner surfaces of the condenser tubes. The sponge balls used had a diameter somewhat greater than the inside diameter of the cooling tubes. However, these balls are gradually worn and, consequently, the diameter of the respective balls is reduced over a period of time, thereby resulting in lowered cleaning effect. This gives a rise to a demand for a suitable sorting apparatus which can sort the unacceptably worn sponge balls from the other sponge balls still having acceptably large diameters to permit the worn sponge balls to be disposed to the outside of the cooling water system.
U.S. Pat. No. 3,841,397 discloses a sorting apparatus, in which a sorting basket, having apertures through which the worn sponge balls are extracted and sorted, is attached only to one side of the internal space of a barrel of the apparatus. This sorting apparatus, however, can operate only at an impractically low sorting efficiency and often fails in the sorting of the worn sponge balls, because the sorting operation relies solely upon a dynamic pressure of the cooling water.